Thermionic method for quantitative determination of ammonia in concrete
SUBSTANCE: method comprises the preliminary moistening of concrete sample and its subsequent heating, in which the thermal emission is carried out in case of discharging of 700 mm Hg and temperature of 80-300°C.
EFFECT: increase of the efficiency and acceleration of analysis.
The invention relates to the field of construction technologies and can be used for the quantitative determination of ammonia in concrete structures used in residential construction.
When using concrete slabs used additive type diamide acetic acid, potash (waste ammonia production), cement with fly ash, etc. Subsequently, in a residential area due to the hydrolysis of ammonia-containing compounds excreted ammonia, which creates uncomfortable conditions for housing. To select the method for reducing ammonia in the premises it is necessary to consider the ammonia content in the concrete.
The known method of determination of ammonia from a sealed temperature-controlled cameras placed in their samples at a temperature of 23±2°C and saturation, expressed as the ratio of the surface area of the sample to the volume of the chamber
While chemical studies of the air environment of the chambers is carried out using a gas chromatograph "Crystal 5000-2 (see Sanitary-hygienic evaluation of polymer and polymer-containing building materials and structures intended for use in the construction of residential, public and industrial buildings. HOWTO. MOO 18.104.22.1689-04, approved. Chief state sanitary doctor of the Russian Federation 06.01.2004).
The disadvantage�known method is the fact, the analysis was carried out for 5 days. In addition, at a temperature of 23±2°C the incomplete hydrolysis and thermal emission of ammonia ineffective. Defined in this way, the concentration of ammonia in mg/m of air does not allow to estimate the mass content of ammonia per ton of overlap that does not allow to choose the optimal technology for the reduction of ammonia in the volume of the room.
Known Kjeldahl method, which consists in heating the nitrogen-containing substance to the boil with enough concentrated sulfuric acid (G. Meir / Analysis and determination of structure of organic substances: the lane with it. / Under the editorship of Professor V. Rodionova and A. Kipriyanov. - 5th ed. - Kharkiv-Kyiv: State .nauch.-tech. publishing house of Ukraine, 1936. - Pp. 129-130).
The disadvantage of this method is the duration of boiling and subsequent distillation. With concentrated sulfuric acid at high temperature partially decomposed to SO3that leads to inaccurate determination of ammonia.
The technical problem solved by the claimed invention is to reduce the time for quantitative determination of ammonia in concrete due to the rapid and complete extraction of ammonia from concrete.
The problem is solved in that thermionic method for the quantitative determination of ammonia in concrete lies in the moist pre�completion of the concrete sample and its subsequent heating, where thermal emission is conducted in the vacuum of 700 mm Hg. CL. and a temperature of 80-300°C.
The essence of the claimed thermionic method for quantitative determination of ammonia in concrete is illustrated by a drawing, which schematically shows the installation of thermionic analysis.
Installation of thermionic analysis includes a chamber 1 made of PTFE and is made in the form of a cylinder with two screw caps. One of the covers of the chamber 1 is provided with two pipes, one of which is connected with made of glass sinks Richter 2. Absorbers Richter 2 filled with a solution of sulfuric acid at a concentration of 0.05 n and a volume of 5 cm3. Camera 1 is placed in an electric furnace with thermostat 3 4.
The claimed method is as follows.
For more rapid and complete excretion of ammonia sample of concrete must moisturize. The wetted sample of concrete is placed in the chamber 1 of the above-described installation of thermionic analysis. To extract the ammonia from the camera 1 connect the vacuum pump 3, which creates a vacuum of 700 mm Hg. V. to intensify the process of emission of ammonia from concrete. At a temperature of 150°C to heat enough 40 minutes at 200°C for 20 minutes. Under these conditions, there is rapid hydrolysis of ammonia-containing components of the concrete. After thermoemission from sinks Richter 2 is transferred to a conical flask and titrated with NaOH solution (caustic soda) concentration of 0.05 D. The amount of ammonia in the sample of concrete is calculated by the formula
With the mass of ammonia in the sample, ug/kg;
m - mass of sample, g;
1,225 - the amount of sulfuric acid in 5 ml of absorbing solution;
V - volume of NaOH used for the titration of a solution from the absorbers Richter, ml;
n1- number of sinks Richter;
n2is the correction factor determined by the formula
V1- the volume of NaOH solution (≈0,005 n), used for titration of 5 ml (0.005 n) sulfuric acid solution (blank solution), ml.
Thus, the claimed invention allows to reduce the time for quantitative determination of ammonia in concrete due to the rapid and complete extraction of ammonia from concrete.
Thermionic method for the quantitative determination of ammonia in concrete, which consists in the preliminary moistening of the concrete sample and its subsequent heating, in which thermal emission is conducted in the vacuum of 700 mm Hg. CL. and a temperature of 80-300°C.
SUBSTANCE: study the interaction of fibreglass with cement stone within the specified time. Previously, the fibreglass is glued on the plastic plate, put into the mould to prepare cement samples and filled with cement slurry. Plastic plate with the glued fibreglass is put in such a way that the fibreglass is in contact with the cement slurry. After solidification the cement specimens are removed from the mould and the fibre is separated from the plate. Then, the fibre is investigated by means of X-ray spectrum analysis and electron microscopy. Method allows to determine the element composition, structure of interaction products of fibre with cement stone. Besides, the resistance of fibreglass compared with the diameter of fibreglass after test with the diameter of raw fibre is evaluated.
EFFECT: invention makes it possible to compare the use of fibreglasses of various compositions as reinforcing materials.
FIELD: testing technology.
SUBSTANCE: invention relates to construction, in particular to determining the parameters of deformation of concrete under conditions of cyclic loading to a level not exceeding the tensile strength of concrete to compression Rb and extension Rbt. Essence: securing a test concrete sample in the form of a prism in the jaws of the test stand is carried out using a centring device which provides a central application of load during loading. The force and deformation of the prism in time is registered by using the dynamometer and the strain-gauge station. The multiple static or dynamic loading is performed by rotating and short-term changing the diameter of the axis in the place of junction of the lever and the compensating element.
EFFECT: simplification of the test method, expanding the functional capabilities of the experimental determination of the static-dynamic characteristics of concrete under conditions of cyclic loading, which consists in alternating application of static and dynamic loads on the sample.
SUBSTANCE: method is realised by fixation of an experimental concrete sample in the form of a prism in clamps of a test bench using an alignment device, providing for central application of stretching load in process of loading, and registration of a force and deformations of the sample in time using a dynamometer and a strain gauge station during loading executed via a lever system in two stages: at the first stage - stepped static loading of the sample to the specified level by means of laying of piece weights onto a load platform, at the second one - instant or stepped dynamic additional loading or unloading by means of short-term variation of the axis diameter in the point of force transfer from the lever to the compensating element, setting, if necessary, the value of movements in the elastic element.
EFFECT: simplified methodology and increased validity and reliability of test results.
5 dwg, 2 ex
FIELD: test equipment.
SUBSTANCE: method relates to test methods of porous water-saturated bodies. It provides for production of a series of concrete specimens, saturation of specimens with water, measurement of specimens, determination of their initial volume, their frosting/defrosting to specified temperatures and recording of deformation. In addition, long-term strength limit of each specimen is determined by a non-destructive method under tension conditions. After defrosting, relative residual deformation of specimens is determined and energy dissipated in unit volume of each specimen is determined during its frosting/defrosting. Then, they are loaded under conditions of uniaxial compression to an extreme load meeting short-term strength limit; energy dissipated in unit volume of the specimen is determined during its compression to an extreme load, and as per the obtained results, grade is calculated as per freeze resistance of each specimen. Grade of concrete as to freeze resistance is determined as an arithmetic mean for grades of specimens.
EFFECT: increasing flexibility, reducing labour intensity and enlarging the number of hardware.
SUBSTANCE: previously prepared samples with various quantity of a filler in a highly dispersed condition for a dry construction mix are placed into a hollow part of metal washers, placed on a metal plate, are compacted by any available method under permanent load of up to 5 MPa per 1 cm2 of sample surface for 10-15 seconds, then marks are applied on the surface of each sample in the form of drops of a solution of various concentration, wetting angles of samples are measured θ, a curve of dependence is built cosθ-1=f(1/σl), where σl - surface tension of the liquid, they determine the angle of inclination of this functional dependence a for each sample of different composition, the curve of dependence a is built on quantity of mix components, and by the point of break of the curve of dependence they define the optimal content of a modifier in the tested object.
EFFECT: reduced number of tests and higher accuracy of mixture composition selection.
2 cl, 2 dwg, 1 tbl
FIELD: test equipment.
SUBSTANCE: at the first stage they determine process mode of manufacturing of ceramic items providing for required operability reserve. Using the produced operability reserve and knowing the suggested time, during which ceramic items must preserve strength parameters, they assess the permissible rated speed of produced reserves consumption. At the second stage, modelling conditions of real operation by means of reproduction of accelerated cyclic variations of temperature with simultaneous impact of possible mechanical factors, they determine actual speed of consumption of the same reserves. Received results of rated permissible speed and actual speed produced for imitation of operation conditions are compared, and results are produced, making it possible to judge on ceramic items.
EFFECT: possibility to determine durability of ceramic items with regard to certain conditions of use.
FIELD: measurement equipment.
SUBSTANCE: invention relates to the field of tests of cement plastering compounds for tensile strength under static loading. Substance: the value of the limit tensile strength is defined by testing steel beams with applied plastering compound according to the scheme of the double-point bend with smooth loading by small steps and fixation of the loading step corresponding to the moment of cracking, and the value of the limit tensile strength is calculated using the formula.
EFFECT: simplified technology for testing, exclusion of the necessity to apply strain metering facilities, higher accuracy of detection of limit tensile strength and completion of tests on plaster layers with specifically small thickness from several mm to 2-3 cm.
1 tbl, 1 dwg
SUBSTANCE: method involves measurement of hardening concrete temperature at given time moments and calculation of concrete strength over three days for hardening in standard conditions by the formula:
EFFECT: reduced labour consumption of monitoring.
1 tbl, 2 dwg
SUBSTANCE: apparatus has at least two sealed chambers with a U-shaped pipe filled with water for releasing excess pressure in the chamber, inlet and outlet gas-distributing manifolds, filters for cleaning the gas-air medium collected from the chambers and the inside of each chamber is fitted with a ventilator and a bath with a saturated salt solution for creating and maintaining given relative air humidity inside the chamber, connected to the sealed chambers through the inlet gas-distributing manifold and, installed on pipes, electromagnetic valves, a carbon dioxide gas source, an automatic gas analyser with a gas flow activator, a gas distribution switch for alternately collecting samples from the chambers and transferring the samples to the gas analyser through the gas flow activator; the gas analyser is also connected to a computer for automatic monitoring of gas concentration in the sealed chambers and feeding gas into the chambers through the electromagnetic valves.
EFFECT: high information value and faster determination.
SUBSTANCE: previously they make at least two samples with different water-cement ratios, thermal cycling and cyclic compression of the sample with the least water-cement ratio are alternated until proportion is disturbed between relative residual deformation and number of cycles, the ratio is calculated between relative reduction of threshold load and relative residual deformation, the concrete grade of frost resistance is determined, as well as relative residual deformation εm, corresponding to reduction of the strength limit specified by the standard for the frost resistance grade of the investigated concrete, they alternate thermal cycling and cyclic compression of other samples with higher water-cement ratios until residual deformation is achieved εm, the number of cycles required for this purpose is accepted as the grade of concrete frost resistance with higher water-cement ratio, using the produced results, they calculate parameters of the function that approximates experimental results.
EFFECT: expanded arsenal of technical facilities for detection of concrete frost resistance dependence on water-cement ratio.
FIELD: measurement equipment.
SUBSTANCE: invention proposes a small-sized instrument for quick assessment of flame-proof properties of flame-proof timber treatment, which consists of a housing made in the form of an open box-type profile, a specimen installation and positioning mechanism, a gas burner activation mechanism and a gas burner installation mechanism. An inclination angle of the specimen installation and positioning mechanism is unchanged relative to a vertical axis of the housing, and additionally, it includes a fixation device of an application point of flame to the specimen with a cut-out in the upper part of the device. All components of the instrument are installed in the cavity of the housing.
EFFECT: providing reliable test results.
SUBSTANCE: invention relates to a method of increasing the thermal-oxidative stability of lubricating oils, in accordance to which samples of lubricating oil are thermostatted by heating in a hermetic cup without mixing for the constant time at atmospheric pressure and fixed temperature, which at each thermostatting of the new sample is step-by-step increased in the range of temperatures, determined by the purpose of the lubricating oil, after heating sampling and testing of the thermostatted samples for resistance to oxidation are carried out. Sampled is a constant weight sample, which then is heated in the presence of air with mixing for a specified time depending on the basic base of the lubricating oil at constant temperature and constant mixing rate, the oxidised samples are photometrically scanned, the coefficient of the light flow absorption is determined, with the determination of the graphical dependence of the change of the parameter of thermo-oxidative stability evaluation on the thermostatting temperature, which is used to determine the optimal temperature of thermostatting, providing maximal resistance to oxidation, characterised by the fact that as a criterion for the evaluation of the thermo-oxidative stability of the lubricating oil taken is a resource of the thermostatted oil work capacity. In the process of testing each new thermostatted sample for resistance to oxidation the sample of the oxidised oil is sampled after equal time intervals, the coefficient of the light flow absorption is determined by photometry, graphical dependences of the light flow absorption coefficient on the oxidation time of the thermostattted oils are built at each temperature of thermostatting, and used to determine the time of reaching the light flow absorption coefficient of the selected value for each oxidised thermostatted oil at different temperatures, the graphical dependence of the time for reaching a selected value of the coefficient of absorption of the light flow of the oxidised thermostatted oils on thermostatting temperature is built with the point of the said dependence with the maximal ordinate, characterising the resource of work capacity being used to determine the temperature of thermostatting, ensuring the maximal resistance to oxidation.
EFFECT: ensuring self-descriptiveness of the increase of the thermo-oxidative stability of lubricating oils and increase of their work capacity resource.
2 cl, 1 tbl, 3 dwg
FIELD: test equipment.
SUBSTANCE: device includes gas generator and operation part with structural material sample, connected in series. Gas generator features removable mixing head. Cylindrical combustion chamber of the gas generator features ignition device and orifice plate. Operation part includes interconnected clamping flange with central hole and flange holding a sample. Central longitudinal axes of flange and sample are coincident. Internal cylindrical surface of clamping flange forms an annular slot with the sample surface, the slot joins a cavity ending with output nozzle through end outlet holes in the flange around sample.
EFFECT: possible maintenance of required pressure-heat loading modes for samples, modelling natural thermal stress state of structural materials of various aggregates operating in alternate heat modes.
SUBSTANCE: method comprises drying a polymer solution until complete evaporation of water; heating the polymer formed after drying the polymer solution, and determining the temperature range of active decomposition of the polymer at a given heating rate, as well as the degree of decomposition of the polymer in said temperature range; drying, performing thermal analysis in the temperature range which includes the temperature range of active decomposition of the polymer, and calculating weight loss of a weighed amount of the sample of porous medium and a weighed amount of the same sample of porous medium after pumping the polymer solution; determining the weight concentration of the polymer that has penetrated the porous medium based on the obtained values.
EFFECT: high accuracy of the obtained data and rapid analysis.
6 cl, 3 dwg
FIELD: measurement equipment.
SUBSTANCE: invention refers to measurement equipment and can be used for automatic determination of metal concentration in ore. According to the method before control of grade of ore, ore passes through conveyor without metal impurities. For heating, area thermal source is used, which width does not exceed conveyor width. After time τspec when heating is finished, measured is average value of temperature based on heated surface of ore without metal T1av. Based on these measurements, formed is calibration curve. Then ore containing metal is continuously supplied to conveyor and heated. After time τspec average value of temperature Tavi is measured on each i frame. Value Tavi-T1av is determined based on calibration curve. Using value (Tavi-T1av), determined is percentage of metal in ore. Besides, a device for implementation of the above method is proposed.
EFFECT: improving reliability of determination of metal concentration in ore.
6 cl, 7 dwg, 1 tbl
FIELD: test equipment.
SUBSTANCE: test bench comprises the appliances to place the unit under test thereat, source of temperature effects with water feed and drain systems arranged under said unit and vertical screen. The latter is arranged along the edges of said source and secured at the columns and elevated above soil to vary the spacing between soil level and source lower edge. Besides it incorporates the system of protection against satellite observation of tests and unit under test. Said system comprises horizontal screen secured from above at vertical screen columns. Said vertical screen consists of metal frame and refractory metal cables spaced in parallel along the frame lengthwise axis and over width exceeding the object overall dimensions. Said cables are braided in crosswise direction at the screen centre part by nichrome bands completely covering the object outlines.
EFFECT: higher accuracy of tests, protection against observation from space.
FIELD: measurement equipment.
SUBSTANCE: invention relates to measurement equipment and can be used for heating and temperature measurement of specimens, which are transparent in an infrared (IR) radiation region. The invention proposes a method for determination of temperature of specimens, which are transparent in an IR region, subject to action with flows of charged particles or electromagnetic radiation, which involves heating or cooling of specimens, measurement of temperature of specimens by means of thermocouples. Specimens are placed in a closed housing made from material with high thermal conductivity and located in a vacuum chamber; air is pumped out till the pressure is 10-3-10-5 Pa; the housing is heated or cooled at the specified temperature interval. Continuous preliminary temperature measurements are performed with thermocouples located outside and inside the housing together with the test specimens till temperature stabilisation moment. Then, final temperature measurements are performed with these thermocouples at a stabilisation moment of the temperature that coincides with the temperature of the test specimen till external action with flows of charged particles or electromagnetic radiation. External action is performed; after external action is completed, a specimen temperature measurement procedure is repeated.
EFFECT: improving accuracy of determination of temperature of specimens transparent in an IR region.
FIELD: measurement equipment.
SUBSTANCE: group of inventions relates to measurement equipment and can be used for testing of fire-resistant efficiency of protective compounds and coatings for timber. The proposed method involves preparation of a specimen, flame action on the specimen, temperature measurement of exhaust gaseous combustion products, measurement of weight of the specimen and determination of weight loss, as per which fire-resistant efficiency is determined. Specimen weight measurement is performed continuously during flame action on the specimen and after the action is completed, and a moment exceeding the limit weight loss established by classification or moment of stabilisation of specimen weight after completion of its burning is taken as a test completion moment. This method is implemented by a device containing a chamber for arrangement of a specimen, a gas burner, an exhaust system with a thermoelectric converter, an instrument for measurement and recording of temperature of exhaust gaseous combustion products. The device is also equipped with a unit for automatic measurement and recording in time of specimen weight during fire tests, which includes a lever mechanism made so that a specimen holder can be installed and connected to a weight measurement instrument connected to the processing and recording unit.
EFFECT: obtaining more accurate data for investigation of a fire protection mechanism.
5 cl, 1 tbl, 4 dwg
FIELD: power engineering.
SUBSTANCE: reactor vessel steel samples are heated to temperature from 300°C, their further ageing is carried out at this temperature within certain time, subsequent tests of samples are carried out for impact bending, and test results are analysed to determine the value of the shift of critical brittleness temperature, at the same time samples of reactor vessel steel in process of ageing at the temperature of reactor vessel operation of 300-320°C are additionally exposed to neutron radiation with flux of 1011-1013 n/cm2·sec for 103 hours, after that they perform baking at the temperature of 400-450°C with duration of at least 30 hours, and assessment of extent of steel embrittlement is determined using the value of shift of critical brittleness temperature ΔTk(t) as a result of thermal ageing for the time making more than 5·105 hours, in accordance with a certain mathematical expression.
EFFECT: increased accuracy of assessment of extent of embrittlement of VVER-1000 reactor vessel embrittlement as a result of thermal ageing.
FIELD: process engineering.
SUBSTANCE: invention relates to monitoring the flue gas composition. This method is suitable for monitoring of steam boiler operation at burning the chlorine-containing fuel. It can also be used at pyrolysis, gasification and the like processes. Composition of flue gases resulted from thermal processes, particularly, at combustion of biological fuel or fuel produced from wastes is monitored by measurement of quantity of particles of definite sizes at, at least, one point in flue gas path. Measured are particles of sizes that are known to be composed of alkaline metal chlorides.
EFFECT: monitoring of alkaline metal chloride compositions in flue gases.
9 cl, 6 dwg
FIELD: measurement technology; material quality control.
SUBSTANCE: method involves testing lubricant material sample in presence of air with stirring constant volume under optimum temperature selected with its dependence on lubricant base and a group of operational properties during a time interval characterizing equal oxidation degree taken into account. Acting in equal time intervals, absorption coefficient is measured for luminous flow absorbed by oxidized lubricant material by applying photometry methods. Viscosity and thermal oxidative stability coefficient Ktos are calculated by using relationship like Ktos = Ka μ0/μin, where Ka is the luminous flow absorption coefficient of oxidized lubricant material; μ0 and μin are the viscosities of oxidized and initial state lubricant, respectively. Graphic dependence of thermal oxidative stability coefficient against luminous flow absorption coefficient of oxidized lubricant material is plotted. Rate of oxidation end products release and their influence upon tested lubricant viscosity growth is determined from plot slope angle tangent with respect to abscissa axis after inflection point. The inflection point coordinates are used for determining the starting point the oxidation end products release begins.
EFFECT: high reliability of estimation method.